Teledyne LXT-280 - Manual (Page 46)

Calibration Correction LXT-280
Teledyne Analytical Instruments 36
5.5 Dissolved Oxygen Units of Measurement
One popular dissolved oxygen unit of measurement is an absolute
value and is expressed as milligrams per liter (mg/l) or parts per million
(ppm). Milligrams per liter and parts per million are two ways of
expressing the same measurement (i.e. 1 mg/l = 0.000001 part of oxygen
per weight). These units of measurement are typically found in
applications where saturated oxygen must be controlled for a chemical
reaction or where the presence of saturated oxygen is detrimental to the
process.
Another unit of measurement is a relative value and is expressed as
percent oxygen saturation or percent solubility. With percent oxygen,
the instrument is calibrated to 100% in air or an oxygen rich
environment. Subsequent measurements are an indication of oxygen
consumption. This unit of measurement is typically used in
environments that must be oxygen-rich, such as bioreactors, fermenters
and waste-water aeration basins.